Potpourri
==> I point out Krugman’s extremely misleading commentary on the fast food strike.
==> You guys all forgot about Human Action’s 65th birthday, didn’t you?
==> This is a neat puzzle about the implications of common knowledge etc.
==> I’m not going to write on it anymore, but a comparable perspective on plea bargains that someone shared in the comments here (sorry I forgot who did).
==> People absolutely flipped out about Matt Ridley’s WSJ article on climate science. Here’s his response (also contains the original piece).
==> Hey did you realize that deflation-ridden Japan has had faster per capita real GDP growth than the US or UK since 2008? David Andolfatto has some interesting remarks in this post, which Scott Sumner linked from EconLog. (Yes yes, I remember Andolfatto said unkind things about Ron Paul. I have a good memory kids.)
This is Potpourri so I guess not offtopic: turns out Krugman will come and face the libertarian wolves after all – at next year’s FreedomFest. He will debate Stephen Moore of the Heritage Foundation.
I had known nothing about Mr Moore. From the little I learned from Google he doesn’t sound too good – at least not from an Austrian libertarian point of view. I guess Krugman wants to claim he has no problems debating a “free-market” economist but then he carefully picks someone who only flies the libertarian flag but is half socialist.
But then again, I may be judging him too soon.
http://freedomfest.com/blog/2014/09/11/debate-2/
I love the common knowledge problem! The intuitive answer is that the queen isn’t revealing any new information, so nothing happens. Everyone on the page gives that answer, and they’re wrong. Rather, the queen’s revelation completes an inductive proof (by contradiction) that each wife’s husband is faithful.
Of course, if a situation like that really existed, my suggestion would be, “holy shnikeys! These women are logically omniscient! Get them jobs as math professors, stat!”
Hmm maybe I *will* write it up Silas. You’re right, people think that the Queen isn’t adding new information. That’s why I like this one.
Actually, to be precise, what adds information is the Queen’s statement *plus* the other wives’ failure to react, which is why it’s hard to make all the requirements of the puzzle explicit. For example, you need to have a “known punishment time interva
So for the two-couple case, each wife reasons:
“Assume my husband is faithful. So the queen must have seen the other man cheat [1]. Since, by assumption, his wife couldn’t have seen my husband cheat, she must think her husband cheated, and so she’ll kill him at [time] … uh, she didn’t, assumption violated, my husband’s unfaithful.”
[1] with me!
A wife must kill her husband on the day she proves his infidelity. The queen informs during one day, so there is new information when the day expires.
First, what do the wives know? For sure, each one knows about at least 99 cases of cheating, and we can assume for each act she knows the identity of each party, though this is probably irrelevant. We have absolutely no reason to believe that each wife knows the special mind powers of the other wives. No wife should assume the other wives will share her reasoning or have equivalent knowledge.
I don’t think you have the 2c case right. W1 reasons about the case where H1 is faithful. In this case, W1 reasons, W2 has full knowledge of H1’s fidelity since W2 is the only possible counterparty. In this case, W1 reasons, W2 can prove via her experience and the queen’s statement that H2 must have cheated. The counterparty knowledge bit presumes heterosexual infidelity.
Likewise, as you mentioned, the wives must all have the capability for perfect reasoning, never fail at perfect reasoning, demand the same for every other wife, and finally treat another wife’s reasoning failure as a logical absurdity. These are only worth mentioning as explicit assumptions in order to proceed with a more well-specified puzzle.
While the two couple logic is clear enough, I don’t see a wedge for more.
We have absolutely no reason to believe that each wife knows the special mind powers of the other wives. No wife should assume the other wives will share her reasoning or have equivalent knowledge.
True: this is why it’s hard to spell out all the assumptions of the “cool” version of the problem. It requires that each wife know about the other wives’ abilities.
Rather, the queen’s revelation completes an inductive proof (by contradiction) that each wife’s husband is faithful.
According to the first sentence of the puzzle every man in the village has cheated on his wife.
Or did you mean unfaithful?
Sorry, you’re right, it should read “unfaithful” there — good catch. I think I was in the middle of writing that she *invalidates* a proof that they’re faithful, but that’s the wrong way to phrase it, and I didn’t correct it.
For a two couple it makes sense what you have written. But for 100 couple it doesn’t make sense to me. Could you elaborate?
There are so many couples that we cannot exclude using “if not this…than that” kind of thinking.
I think I get it. It’s because all women know about all other men’s infidelity other than their own’s. So all women know of 99 other males cheated. It is similar to the case of the two couple scenario.
But if there were only 99 males that cheated and one that didn’t, this would get unsolvable?
I’ve been enjoying the Matt Ridley piece and the resultant cat fight as evidence of how neurotic the global warming alarmists are. His point is obvious and simple to deduce. Imagine adding together two functions: one that is linear or parabolic and constitutes your signal, and one is a sine wave. The line/parabola represents AWG and the sine wave represents the heat that is alternately absorbed and release by the Atlantic ocean current. The first is your signal, and the second is essentially noise.
The increase over time for one half of the sine wave’s wavelength (from trough to peak) is about equal to the increase over the same unit of time for the line. If you measure the added functions together during the time when the sine wave is increasing, it will appear that your signal is going up twice as fast. Likewise, measuring during the time that the sine wave is decreasing will cause the resulting function to flatten out. Plotted over multiple wavelengths, this takes on a stair-step pattern. Fair enough, and climate alarmists admit as much.
What they fail to disclose (surely not coincidence), is that the models are all built on the assumption that there is no sine wave function, and that the increase that occurred was all signal, no noise. Knowing that this cycle exists, we can see that the total warming must be an average of the increasing and decreasing phases of the sine wave, and that its magnitude must be only about half of what is observed during the increasing phase.
According to this site, on an adjusted basis, global warming has still been occurring (graph ends in 2011):
http://static.skepticalscience.com/pics/FR11_All.gif
Is that their way of saying “other things being equal, anthropogenic global warming is still happening”?
Yup.
Mini shout-out to Robert P. Murphy
https://www.youtube.com/watch?v=qhxC-SLVszY
Here’s to Human Action may I one day finish it! Combine the ambition and rigor of Wittgenstein and the thoroughness of, well, Mises, and out pops Human Action. I kid 😉
While it’s neither watertight nor completely persuasive, I find it hard to argue with. It is extremely powerful and clear for readers familiar with philosophy, logic, and epistemology. I don’t agree with everything, there are some missteps, not every section is timeless, some arguments seem to hinge solely on repeated assertion, and the not infrequent tedium saps my will. But these concerns are trifling for a powerful work of great breadth and depth.
I am always curious to know, for my most serious intellectual opponents capable of following logical argument, where exactly in Human Action do they personally lose the plot? This is not a rhetorical question. The premises are easily challenged, though I would suggest that replacement is much more difficult. If not, surely hundreds and hundreds of pages of logical argument cannot be error-free.
What econ books outside the Austrian tradition take a similar approach, tracing their conclusions all the way back to axioms, or at least attempt to do so, or sketch an outline even? Because arguments have steps, and early errors compound and confound, and HA is so broad and deep, as a whole I would rate it as 10-50% true. Yet if we could imagine a work of similar scope that is 100% true, HA is by far the closest.
One problem I have with it is that he describes action but applies it to behaviour. What he says about action may be OK, but since there is no reason to think that human behaviour is all action, and very good reason to think that human behaviour is much more than action, it seems to have little relevance to human behaviour.
Recommending again in case anyone missed it – anyone who hasn’t read “Torture and Plea Bargaining” should. It’s a justifiable classic.
http://chicagounbound.uchicago.edu/cgi/viewcontent.cgi?article=1005&context=crosskey_lectures
” Hey did you realize that deflation-ridden Japan has had faster per capita real GDP growth than the US or UK since 2008?”
And Japan has had a stagnating then declining population since 2004, not speculator real GDP growth:
http://socialdemocracy21stcentury.blogspot.com/2014/09/japanese-real-per-capita-gdp-and.html
No great mystery here.
And it does not necessarily prove or imply that deflation is healthy for an economy.
I thought I smelled troll.
“And it does not necessarily prove or imply that deflation is healthy for an economy.”
And it does not necessarily prove or imply that deflation is bad for an economy.
Off topic but I needed to share
http://gene-callahan.blogspot.com/2014/09/calling-someone-who-thinks-that-there.html
I’ve just been banned from Gene’s blog for suggesting that if he thinks the US govt is the right body to be regulating what the optimal level of immigration is, then perhaps he would also support the US govt regulating the optimal calorie intake of its citizens.
Apparently that was too silly a suggestion to be allowed into his comments section.